Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes
  • C09J175/06—Polyurethanes from polyesters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
  • C08G18/0823—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups containing carboxylate salt groups or groups forming them
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
  • C08G18/0828—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups containing sulfonate groups or groups forming them
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
  • C08G18/12—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step using two or more compounds having active hydrogen in the first polymerisation step
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/2805—Compounds having only one group containing active hydrogen
  • C08G18/2815—Monohydroxy compounds
  • C08G18/283—Compounds containing ether groups, e.g. oxyalkylated monohydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
  • C08G18/3203—Polyhydroxy compounds
  • C08G18/3206—Polyhydroxy compounds aliphatic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
  • C08G18/3225—Polyamines
  • C08G18/3228—Polyamines acyclic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
  • C08G18/3225—Polyamines
  • C08G18/3253—Polyamines being in latent form
  • C08G18/3259—Reaction products of polyamines with inorganic or organic acids or derivatives thereof other than metallic salts
  • C08G18/3265—Reaction products of polyamines with inorganic or organic acids or derivatives thereof other than metallic salts with carbondioxide or sulfurdioxide
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
  • C08G18/3855—Low-molecular-weight compounds having heteroatoms other than oxygen having sulfur
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
  • C08G18/4236—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups
  • C08G18/4238—Polycondensates having carboxylic or carbonic ester groups in the main chain containing only aliphatic groups derived from dicarboxylic acids and dialcohols
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
  • C08G18/4263—Polycondensates having carboxylic or carbonic ester groups in the main chain containing carboxylic acid groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/721—Two or more polyisocyanates not provided for in one single group C08G18/73 - C08G18/80
  • C08G18/722—Combination of two or more aliphatic and/or cycloaliphatic polyisocyanates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
  • C08G18/78—Nitrogen
  • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
  • C08G18/797—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing carbodiimide and/or uretone-imine groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
  • C08L75/04—Polyurethanes
  • C08L75/06—Polyurethanes from polyesters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2170/00—Compositions for adhesives
  • C08G2170/80—Compositions for aqueous adhesives

Definitions

• the invention relates to an aqueous adhesive formulation in the form of an aqueous dispersion containing at least the following dispersed components: (A) at least one polymer selected from the group consisting of polyurethane polymers, vinyl polymers, polyester polymers and/or mixtures of at least two thereof, wherein the polymer has a partial acid number of ⁇ 1.25 mg KOH/g, determined according to DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture); (B) at least one semi-crystalline or crystalline polyurethane polymer containing carboxyl groups, which has a melting temperature in the range from 35 to 80 °C, an enthalpy of fusion of ⁇ 15 J/g, in each case determined by means of DSC (differential scanning calometry) at a heating rate of 20 K/min in accordance with DIN EN ISO 11357-1:2017 (2017-02), and a partial acid number in the range from 1.25 mg KOH/g to 25 mg KOH/g
• Adhesives based on aqueous polyurethane dispersions have established themselves worldwide in demanding industrial applications, for example in shoe manufacturing, bonding furniture parts, bonding parts for automotive interiors, film lamination or bonding textile substrates.
• the production of aqueous polyurethane or polyurethane-polyurea dispersions is well known.
• the thermal activation process is often used.
• the dispersion is applied to the substrate and, after the water has completely evaporated, the adhesive layer is activated by heating, e.g. with an infrared radiator, and converted into an adhesive state.
• the temperature at which the adhesive film becomes sticky is called the activation temperature.
• the adhesives used in this process often contain crystalline components that are in molten form at or above the activation temperature.
• Adhesives based on aqueous polyurethane or polyurethane-polyurea dispersions which are suitable for the application of the thermal activation process, are US-A 4 870 129 described. According to this, aqueous polyurethane or polyurethane-polyurea dispersions can be obtained by using special mixtures of diisocyanates and polyol components according to the acetone process. The films obtained from these have good activatability.
• wet bonding can also be used, i.e. the bonding is carried out immediately after the adhesive is applied.
• the parts to be joined must be mechanically fixed until the adhesive has set. This method is often used to bond wood or textile substrates.
• US4870129A discloses an adhesive that contains a crosslinker containing isocyanate groups and an aqueous polyurethane dispersion containing hydroxyl groups, the crosslinker increasing the crosslinking density of the adhesive and thereby improving the hydrolysis resistance of the coating formed therefrom.
• the disadvantage is that the crosslinking reaction of the isocyanate groups with water and hydroxyl groups begins immediately after the adhesives are produced and therefore these adhesives only have a short processing time, usually a few hours. This is disadvantageous because any adhesives that have been produced and not used up can no longer be used after the pot life has expired.
• US6348548 discloses the use of an aqueous dispersion containing at least one solid surface-passivated polyisocyanate and at least one isocyanate-reactive polymer for producing a potentially active layer or powder with storage stability.
• a disadvantage of this procedure is that it requires heating for a long time at high temperature for activation after the said components have been applied to a substrate surface. It is therefore also not suitable for bonding substrates that can be damaged by heating to elevated temperatures.
• WO2020035573A1 describes an adhesive formulation consisting of at least one polyurethane dispersion, a surface-deactivated solid isocyanate and a polycarbodiimide.
• the activation temperatures can be lowered in this case, but the use of surface-deactivated solid isocyanates is economically disadvantageous because they are complex to produce and expensive. Furthermore, they usually contain residual monomers of diisocyanates due to the manufacturing process, which are undesirable for reasons of occupational hygiene.
• aqueous polyurethane dispersion containing terminal and pendant carboxyl groups.
• the aqueous polyurethane dispersion can be crosslinked with polyarbodiimides to improve the heat resistance of the Polyurethane dispersion coating.
• Special blends with polymers that do not contain carboxyl groups are not explicitly mentioned.
• Crosslinking occurs through reaction of the carboxyl groups in the polyurethane polymer with the carbodiimide groups in the polycarbodiimide after film formation. This is described, for example, in Meier-Westhues et al. Polyurethanes, 2nd edition, Vincentz Network Hannover, 2019 pages 342-343 The "open time” is given here as " ⁇ 1h”.
• EP2186841A1 describes dispersed polyurethanes or polyurethane-polyureas with terminal carboxyl groups and additional pendant sulfonate and/or carboxylate groups. The focus of the patent is on the pendant nature of the carboxyl and carboxylate groups. Blends with polymers that do not contain carboxyl groups are not explicitly mentioned.
• polyester polyurethane dispersions containing carboxyl groups A general disadvantage of using polyester polyurethane dispersions containing carboxyl groups is the increased tendency for hydrolysis of the polyester groups, which is catalyzed by the carboxyl groups, especially at high temperatures. The resulting reduction in molecular weight leads to reduced heat resistance in use. As a result, these products should be stored at temperatures below 30 degrees °C and used as quickly as possible.
• US20160168434A1 describes an adhesive formulation consisting of a mixture of a polyurethane dispersion 1 containing a polyurethane with isocyanate-reactive groups, and a polyurethane dispersion 2 containing a polyurethane with carboxyl groups and further isocyanate-reactive groups, as well as a surface-deactivated solid isocyanate.
• the use of the surface-deactivated solid isocyanate in the adhesive formulations is necessary in order to achieve good adhesion to metallic substrates.
• the use of polyurethane dispersions containing carboxyl groups is described, but the simultaneous use of crosslinkers that can react with acid groups is not mentioned.
• the use of polyurethanes containing carboxyl groups aims at improved adhesion to metallic substrates. A very high concentration of carboxyl groups is necessary to achieve the desired effect.
• US20220177751A1 describes latent-reactive adhesives based on crystalline polyurethane dispersions and solid polycarbodiimides.
• the use of non-carboxyl groups containing polymer dispersions in addition to those containing carboxyl groups is not explicitly discussed. Due to the tendency to sedimentation in dispersion and blocking during storage, the processing and use of solid polycarbodiimides is disadvantageous.
• the present invention was therefore based on the object of providing aqueous polyurethane-based adhesives which are suitable for use in thermal activation processes with low activation temperatures and times, lead to particularly heat-resistant bonds and overcome the disadvantages of the prior art by having a long pot life and open time and without the use of surface-deactivated solid polyisocyanates, as well as with a reduced proportion of polyester polyurethane dispersions containing carboxylic acid groups.
• the described adhesive formulations according to the invention consisting of or containing aqueous polymer dispersions, preferably aqueous polyurethane or polyurethane-polyurea dispersions in combination with at least one polycarbodiimide, are suitable as adhesives according to the thermal activation process and have an open time of several days to weeks. Furthermore, it was surprisingly found that an adhesive formulation according to the invention can be produced using the kit of parts according to the invention.
• polyurethane polymer means both polyurethane polymers and polyurethane-urea polymers or polyurethane-polyurea polymers.
• aqueous dispersion means an aqueous dispersion, aqueous emulsion, aqueous suspension, or an intermediate state/intermediate form thereof, preferably an aqueous dispersion, aqueous emulsion and/or aqueous suspension.
• dispersion is particularly preferably understood to mean an aqueous emulsion and/or an aqueous suspension.
• polyurethane dispersion refers to both polyurethane and polyurethane-(poly)urea dispersions.
• open time is understood to mean the time after drying of an adhesive during which the adhesive is still able to flow sufficiently under the usual conditions of heat-induced bonding and wetting of a substrate to be bonded is still possible under moderate pressure, so that, for example, a high bond strength of bonded substrates can be achieved.
• storage-stable pre-coatings of substrate surfaces, self-supporting latent-reactive adhesive films or reactive adhesive powders are characterized in that after storage under standard conditions (23 °C, 50% relative humidity) after more than 24 hours, particularly preferably after more than 7 days, they are still suitable for flowing sufficiently under the usual conditions for heat-induced bonding and wetting of a substrate to be bonded is still possible under moderate pressure.
• the adhesive In heat-induced bonding, the adhesive is usually heated to a temperature between 40 and 120 °C and the substrates are pressed together with a moderate pressure, for example 0.5 to 10 bar.
• a polymer, in particular polyurethane polymer is referred to as partially crystalline or crystalline if it has a melting peak in the DSC measurement according to DIN EN ISO 11357-1:2017 (2017-02) at a heating rate of 20 K/min in the first heating.
• the melting peak is caused by the melting of regular substructures in the polymer, in particular polyurethane polymer.
• a polymer, in particular polyurethane polymer is referred to as partially crystalline if it has a melting peak in the DSC measurement according to DIN EN ISO 11357-1:2017 (2017-02) at a heating rate of 20 K/min in the first heating and has a glass transition in the third heating.
• the melting temperature of the at least one polyurethane polymer (B) contained in the formulation according to the invention is in the range from 35 to 80 °C, preferably 40 to 70 °C, particularly preferably 42 to 55 °C.
• the enthalpy of fusion of the at least one polyurethane polymer (B) is ⁇ 15 J/g.
• the at least one polymer (A), preferably polyurethane polymer (A), preferably has a glass transition temperature of in the range from -100 °C to 80 °C, and when the polymer (A) is preferably at least one partially crystalline polyurethane polymer (A), a melting temperature in the range from 35 to 80 °C and an enthalpy of fusion of ⁇ 15 J/g.
• the melting temperature and the melting enthalpy are determined during the first heating starting from a starting temperature of -100 °C in the DSC measurement according to DIN EN ISO 11357-1:2017 (2017-02) at a heating rate of 20 K/min.
• the glass transition temperature is determined during the third Heating starting from a starting temperature of -100 °C in the DSC measurement according to DIN EN ISO 11357-1:2017 (2017-02) at a heating rate of 20 K/min.
• DIN EN ISO 11357-1:2017 the standard part DIN EN ISO 11357-2:2020-08 is used to determine the glass transition temperature and the standard part DIN EN ISO 11357-3:2018-07 is used to determine the melting temperature and the enthalpy of fusion.
• samples are taken from a polymer film that has been dried to constant weight at 23 °C and 50% relative humidity and then stored in a dry box for 3 days at 0% relative humidity.
• the expressions “comprising” or “containing” preferably mean “consisting essentially of” and particularly preferably “consisting of”. It should be noted that the features listed individually in the claims can be combined with one another in any technically reasonable manner (including across category boundaries, for example between method and device) and show further embodiments of the invention. The description additionally characterizes and specifies the invention.
• the aqueous adhesive formulation according to the invention has a partial acid number in the range from 0.5 mg KOH/g to 10 mg KOH/g, preferably in the range from 1.0 mg KOH/g to 10 mg KOH/g, particularly preferably in the range from 2 mg KOH/g to 6 mg KOH/g, determined according to DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• the sum of the amounts of components (A), (B), (C) and optionally (D) in the aqueous adhesive formulation according to the invention is at least 30% by weight, preferably in the range from 30% by weight to 70% by weight, particularly preferably in the range from 35% by weight to 65% by weight, even more preferably in the range from 35% by weight to 65% by weight, based on the total weight of the aqueous adhesive formulation.
• the aqueous adhesive formulation according to the invention optionally further contains at least one additive which is different from components (A), (B), (C) and (D).
• the composition according to the invention contains organic solvents in a concentration of ⁇ 5% by weight, preferably ⁇ 1% by weight, based on the total weight of the aqueous adhesive formulation. In a further preferred embodiment, the composition according to the invention contains no acetone and/or organic polar aprotic solvents.
• aqueous adhesive formulation according to the invention and the kit-of-parts according to the invention contain as component (A) at least one polymer selected from the group consisting of polyurethane polymers, vinyl polymers, polyester polymers and/or mixtures of at least two thereof, wherein the polymer has a partial acid number of ⁇ 1.25 mg KOH/g, determined according to DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• the mixture of these polymers has an average partial acid number of ⁇ 1.25 mg KOH / g, determined according to DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture), wherein preferably each of the polymers in the mixture has a partial acid number of ⁇ 1.25 mg KOH / g, determined according to DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• any polymer known to the person skilled in the art selected from the group consisting of polyurethane polymers, vinyl polymers, polyester polymers and/or mixtures of at least two thereof can be used in the adhesive formulation according to the invention.
• Suitable vinyl polymers are all vinyl polymers known to the person skilled in the art which have a partial acid number of ⁇ 1.25 mg KOH / g, determined according to DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• a "vinyl polymer” is understood to mean a polymer that is formed by addition polymerization [usually by a free-radical process] of at least one ethylenically unsaturated monomer.
• a vinyl monomer is therefore understood here to mean an ethylenically unsaturated monomer.
• olefins such as ethylene or propylene
• vinyl halides such as vinylidene chloride and vinyl chloride
• ethylenically unsaturated amides vinyl est
• vinyl polymers are suitable: ethylene, butyl acrylate, methyl methacrylate, vinyl acetate.
• Suitable polyester polymers are all polyesters known to the person skilled in the art which have a partial acid number of ⁇ 1.25 mg KOH / g, determined in accordance with DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• Suitable polyester polymers are obtainable, for example, by reacting monomeric dicarboxylic acids with polyhydric alcohols. Aliphatic and aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, adipic acid, sebacic acid, succinic acid as well as 1,4-butanediol, 1,6-hexanediol and ethylene glycol are particularly suitable as structural components.
• Suitable polyurethane polymers are all polyurethanes known to the person skilled in the art which have a partial acid number of ⁇ 1.25 mg KOH / g, determined in accordance with DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• a polyurethane polymer suitable as component (A) is/are generally one or more polyurethanes in the narrower sense, i.e. polymers obtained by polymerizing polyols and polyisocyanates, but they can also be polymers in which monoamines and/or diamines are used as structural components, optionally as chain extenders.
• the polyurethane polymer of component (A) is therefore generally at least one polyurethane, at least one polyurea and/or at least one polyurethaneurea.
• Component a) is typically used in amounts of 0.5 wt.% to 10 wt.%, preferably 0.5 wt.% to 4 wt.%, based on the water- and solvent-free polyurethane or polyurethane-polyurea.
• Component b) is typically used in amounts of 50 wt.% to 95 wt.%, preferably 65 wt.% to 92 wt.%, based on the water- and solvent-free polyurethane or polyurethane-polyurea.
• Component c) is typically used in amounts of 4 wt.% to 25 wt.%, preferably 6 wt.% to 15 wt.%, based on the water- and solvent-free polyurethane or polyurethane-polyurea.
• Component d) is typically used in amounts of 0 wt.% to 10 wt.%, preferably 0 wt.% to 5 wt.%, based on the water- and solvent-free polyurethane or polyurethane-polyurea.
• Component e) is typically used in amounts of 0 wt.% to 10 wt.%, preferably 0 wt.% to 5 wt.%, based on the water- and solvent-free polyurethane or polyurethane-polyurea.
• Suitable isocyanate-reactive components a) which carry at least one ionic or potentially ionic group are mono- and diaminocarboxylic acids, mono- and dihydroxysulfonic acids, mono- and diaminosulfonic acids and mono- and dihydroxyphosphonic acids or mono- and diaminophosphonic acids and their alkali and ammonium salts.
• N-(2-aminoethyl)- ⁇ -alanine N-(2-aminoethyl)-2-aminoethanesulfonic acid
• N-(2-aminoethyl)-2-aminoethanecarboxylic acid ethylenediaminepropyl- or -butylsulfonic acid, 1,2- or 1,3-propylenediamine- ⁇ -ethylsulfonic acid, malic acid, citric acid, glycolic acid, lactic acid, glycine, alanine, taurine, lysine, 3,5-diaminobenzoic acid, an addition product of IPDI and acrylic acid ( EP-A 0 916 647 , Example 1) and its alkali and/or ammonium salts; the adduct of sodium bisulfite with butene-2-diol-1,4, polyethersulfonate, the propoxylated adduct of 2-butenediol and NaHSO
• Sodium, potassium and/or lithium hydroxide as well as tertiary amines such as triethylamine, dimethylcyclohexylamine and ethyldiisopropylamine are well suited for salt formation.
• Other amines can also be used for salt formation, such as ammonia, diethanolamine, triethanolamine, dimethylethanolamine, methyldiethanolamine, aminomethylpropanol and mixtures of the above and other amines. It makes sense to add these amines only after the isocyanate groups have largely been converted.
• Suitable isocyanate-reactive components a) which carry at least one ionic or potentially ionic group are also mono- and dihydroxycarboxylic acids and their alkali metal salts. Examples are dimethylolpropionic acid, dimethylolbutyric acid, hydroxypivalic acid and their alkali metal salts. Sodium, potassium and/or lithium hydroxide are well suited for salt formation.
• Component a) is contained in the polyurethane polymer suitable as component (A) preferably at 0.5 wt.% to 10 wt.%, more preferably at 0.5 wt.% to 4 wt.% and particularly preferably at 0.5 wt.% to 3.75 wt.%, based on the total weight of the polyurethane polymer.
• the polyurethane polymers suitable as component (A) are prepared from a polyol and a polyisocyanate.
• polyols include polyester polyols, polyether polyols, and combinations thereof.
• Suitable polyester polyols include crystallizing and amorphous polyester polyols.
• Suitable diol and/or polyol components b) are compounds with at least two hydrogen atoms reactive towards isocyanates and an average molecular weight of 62 to 18,000, preferably 62 to 4,000 g/mol.
• suitable structural components are polyethers, polyesters, polycarbonates, polylactones and polyamides.
• Preferred polyols b) have 2 to 4, particularly preferably 2 to 3 hydroxyl groups. Mixtures of various such compounds are also possible.
• Suitable polyester polyols are in particular linear polyester diols or also slightly branched polyester polyols, as are prepared in a known manner from aliphatic, cycloaliphatic or aromatic di- or polycarboxylic acids, such as succinic, methylsuccinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, nonanedicarboxylic, decanedicarboxylic, terephthalic, isophthalic, o-phthalic, tetrahydrophthalic, hexahydrophthalic, cyclohexanedicarboxylic, maleic, fumaric, malonic or trimellitic acid, and acid anhydrides, such as o-phthalic, trimellitic or succinic anhydride or mixtures thereof with polyhydric alcohols, such as ethanediol, di-, tri-, tetraethylene glycol, 1,2-propanediol, di-,
• Cycloaliphatic and/or aromatic di- and polyhydroxyl compounds can of course also be used as polyhydric alcohols for the production of polyester polyols.
• the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof can also be used to produce the polyesters.
• the polyester polyols can also be homopolymers or copolymers of lactones, which are preferably obtained by addition of lactones or lactone mixtures, such as butyrolactone, ⁇ -caprolactone and/or methyl- ⁇ -caprolactone to the suitable di- and/or higher-functional starter molecules, such as the low molecular weight, polyhydric alcohols mentioned above as structural components for polyester polyols.
• lactones or lactone mixtures such as butyrolactone, ⁇ -caprolactone and/or methyl- ⁇ -caprolactone
• suitable di- and/or higher-functional starter molecules such as the low molecular weight, polyhydric alcohols mentioned above as structural components for polyester polyols.
• the corresponding polymers of ⁇ -caprolactone are preferred.
• polyester polyols which contain isophthalic acid and/or terephthalic acid as structural components, as well as neopentyl glycol, ethylene glycol, butanediol and/or hexanediol.
• Polycarbonates containing hydroxyl groups can also be considered as polyhydroxyl components, e.g. those that can be produced by reacting diols such as 1,4-butanediol and/or 1,6-hexanediol with diaryl carbonates such as diphenyl carbonate, dialkyl carbonates such as dimethyl carbonate or phosgene.
• diols such as 1,4-butanediol and/or 1,6-hexanediol
• diaryl carbonates such as diphenyl carbonate
• dialkyl carbonates such as dimethyl carbonate or phosgene.
• the hydrolysis resistance of the polyurethane or polyurethane-urea dispersion adhesives can be improved by at least partially using polycarbonates containing hydroxyl groups.
• Polycarbonates prepared by reacting 1,6-hexanediol with dimethyl carbonate are preferred.
• Suitable polyether polyols include, for example, the polyaddition products of styrene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide, epichlorohydrin, and their mixed addition and graft products, as well as the polyether polyols obtained by condensation of polyhydric alcohols or mixtures thereof and the polyether polyols obtained by alkoxylation of polyhydric alcohols, amines and amino alcohols.
• Polyether polyols suitable as building components A) are the homopolymers, mixed polymers and graft polymers of propylene oxide and ethylene oxide, which are obtainable by addition of the epoxides mentioned to low molecular weight di- or triols, as mentioned above as building components for polyester polyols, or to higher-functional low molecular weight polyols such as pentaerythritol or sugar, or to water.
• Particularly preferred di- or higher functional polyols b) are polyester polyols, polylactones and polycarbonates.
• suitable components b) are low molecular weight diols, triols and/or tetraols such as ethanediol, di-, tri-, tetraethylene glycol, 1,2-propanediol, di-, tri-, tetrapropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-dihydroxycyclohexane, 1,4-dimethylolcyclohexane, 1,8-octanediol, Decanediol-1,10, dodecanediol-1,12, neopentyl glycol, 1,4-cyclohexanediol, 1,4
• Reaction products of the above-mentioned polyols, in particular the low molecular weight polyols, with ethylene and/or propylene oxide can also be used as polyols.
• the low molecular weight components b) have a molecular weight of 62 to 400 g/mol and are preferably used in combination with the polyester polyols, polylactones, polyethers and/or polycarbonates described above.
• Polyol component b) is contained in the polyurethane polymer suitable as component (A) preferably at 50 wt.% to 95 wt.%, more preferably at 65 wt.% to 92 wt.% and particularly preferably at 75 wt.% to 90 wt.%, based on the total weight of the polyurethane polymer.
• Diisocyanates Y(NCO) 2 are preferably used, where Y is a divalent aliphatic hydrocarbon radical having 4 to 12 carbon atoms, a divalent cycloaliphatic hydrocarbon radical having 6 to 15 carbon atoms, a divalent aromatic hydrocarbon radical having 6 to 15 carbon atoms or a divalent araliphatic hydrocarbon radical having 7 to 15 carbon atoms.
• diisocyanates examples include tetramethylene diisocyanate, methylpentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 4,4'-diisocyanatodicyclohexylmethane, 4,4'-diisocyanatodicyclohexylpropane-(2,2), 1,4-diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanatodiphenylmethane, 2,2'- and 2,4'-diisocyanatodiphenylmethane, tetramethylxylylene diisocyanate
• polyurethane chemistry or also modified polyisocyanates known per se, for example those containing carbodiimide groups, allophanate groups, isocyanurate groups, urethane groups and/or biuret groups.
• polyisocyanates that contain heteroatoms in the residue linking the isocyanate groups and/or have a functionality of more than 2 isocyanate groups per molecule are also suitable.
• the former can be modified, for example, by simple Polyisocyanates with uretdione, isocyanurate, urethane, allophanate, biuret, carbodiimide, imino-oxadiazinedione and/or oxadiazinetrione structure, produced from aliphatic, cycloaliphatic, araliphatic and/or aromatic diisocyanates and composed of at least two diisocyanates.
• An example of a non-modified polyisocyanate with more than 2 isocyanate groups per molecule is 4-isocyanatomethyl-1,8-octane diisocyanate (nonane triisocyanate).
• Preferred diisocyanates c) are aliphatic and araliphatic diisocyanates such as hexamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 4,4'-diisocyanatodicyclohexylmethane, 4,4'-diisocyanatodicyclohexylpropane-(2,2), and mixtures consisting of these compounds, which may optionally contain proportions of 2,4-diisocyanatotoluene and/or 2,6-diisocyanatotoluene.
• diisocyanates c) are aliphatic and araliphatic diisocyanates such as hexamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-
• Very particularly preferred components c) are mixtures of hexamethylene diisocyanate and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, and mixtures of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane and/or 4,4'-diisocyanatodicyclohexylmethane and/or 2,4-diisocyanatotoluene and/or 2,6-diisocyanatotoluene.
• Component c) is present in the polyurethane polymer suitable as component (A) preferably in amounts of from 4% by weight to 25% by weight, preferably from 6% by weight to 15% by weight and particularly preferably in amounts of from 8% by weight to 15% by weight, based on the total weight of the polyurethane polymer.
• Suitable components d) are mono-, di-, trifunctional amines and/or mono-, di-, trifunctional hydroxyamines, such as aliphatic and/or alicyclic primary and/or secondary monoamines such as ethylamine, diethylamine, the isomeric propyl and butylamines, higher linear aliphatic monoamines and cycloaliphatic monoamines such as cyclohexylamine.
• Further examples are amino alcohols, i.e.
• ethanolamine N-methylethanolamine, diethanolamine, diisopropanolamine, 1,3-diamino-2-propanol, N-(2-hydroxyethyl)ethylenediamine, N,N-bis(2-hydroxyethyl)ethylenediamine and 2-propanolamine.
• diamines and triamines such as 1,2-ethanediamine, 1,6-hexamethylenediamine, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (isophoronediamine), piperazine, 1,4-diaminocyclohexane, bis-(4-aminocyclohexyl)-methane and diethylenetriamine.
• Adipic acid dihydrazide, hydrazine and hydrazine hydrate are also possible. Mixtures of several of the above-mentioned compounds can of course also be used, possibly also together with compounds d) not mentioned.
• Preferred components d) are 1,2-ethanediamine, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, diethylenetriamine, diethanolamine, ethanolamine, N-(2-hydroxyethyl)ethylenediamine and N,N-bis(2-hydroxyethyl)ethylenediamine.
• Components d) serve as chain extenders preferably to build up higher molecular weights or as monofunctional compounds to limit molecular weights and/or optionally to incorporate additional reactive groups, such as free hydroxyl groups, as additional crosslinking sites.
• Component d) is present in the polyurethane polymer suitable as component (A) preferably in amounts of from 0% by weight to 10% by weight, preferably from 0% by weight to 5% by weight and particularly preferably in amounts of from 0.25% by weight to 4% by weight, based on the total weight of the polyurethane polymer.
• Difunctional polyol components with a molecular weight of 62 to 399 g/mol that are suitable as structural component e) are, for example, the polyols mentioned for the production of polyester polyols b).
• Low molecular weight polyester diols, polyether diols, polycarbonate diols or other polymer diols are also suitable in principle, provided they have a molecular weight of 62 to 399 g/mol.
• Component e) is preferably present in the polyurethane polymer suitable as component (A) in amounts of from 0% by weight to 10% by weight, preferably from 0% by weight to 5% by weight, based on the total weight of the polyurethane polymer.
• component e) can, for example, lead to polyurethane polymers which contain additional reactive groups in addition to the reactive groups contained therein, which enables, for example, the application of different cross-linking mechanisms (dual cure) in order to achieve special properties, such as a two-stage, possibly staggered curing or a particularly high cross-linking density.
• the polyurethane polymers suitable as component (A) can be present and used as a solid or as a dispersion in a liquid medium.
• the polyurethane polymers are preferably provided as aqueous dispersions.
• Such polyurethane dispersions suitable as component (A) preferably have non-volatile fractions of 15% by weight to 70% by weight, preferably 20% by weight to 60% by weight, based on the total weight of the aqueous polyurethane dispersion.
• the pH at 23 °C is preferably in the range from 4 to 11, preferably 5 to 8.
• the average particle sizes measured by laser diffraction in accordance with ISO 13320 (laser diffraction) with the Malvern Mastersizer 3000 are usually in the range from 20 nm to 750 nm, preferably in the range from 30 nm to 450 nm.
• Polyurethane or polyurethane-urea dispersions suitable as component (A) can be prepared, for example, by reacting components a), b), c) and optionally e) in a one- or multi-stage reaction to form an isocyanate-functional prepolymer, which is then reacted with component d) in a one- or two-stage reaction and then is dispersed in or with water, whereby any solvent used can be partially or completely removed by distillation during or after dispersion.
• Polyurethane dispersions suitable as component (A) are preferably anionically stabilized polyurethane dispersions.
• An example of a commercially available polyurethane dispersion suitable as component (A) is Dispercoll ® U 8755, available from Covestro GmbH AG.
• the at least one polymer (A) has no carboxyl groups and/or carboxylate groups.
• the at least one polymer (A) is selected from the group consisting of polyurethane polymers, polyacrylate polymers, polymethacrylate polymers, polyvinyl acetate polymers, polyester polymers and/or mixtures of at least two thereof.
• the at least one polymer (A) is selected from the group consisting of polyurethane polymers, polyacrylate polymers, polymethacrylate polymers and/or mixtures of at least two thereof.
• the at least one polymer (A) is at least one polyurethane polymer.
• the at least one polymer (A) has a partial acid number in the range from 0 mg KOH/g to 1 mg KOH/g, preferably in the range from 0 mg KOH/g to 0.05 mg KOH/g, in each case determined according to DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• the average molecular weight (Mw) of polymer (A) is ⁇ the average molecular weight (Mw) of polyurethane polymer (B), preferably the average molecular weight (Mw) of polymer (A) is greater than the average molecular weight (Mw) of polyurethane polymer (B), each determined according to DIN EN ISO 13885-2 (2021-11) with N,N-dimethylacetamide as eluent and polystyrene as standard.
• the at least one polymer (A) has an average molecular weight (Mw) in the range from 70,000 g/mol to 350,000 g/mol, preferably in the range from 100,000 g/mol to 350,000 g/mol, particularly preferably in the range from 200,000 g/mol to 350,000 g/mol, even more preferably in the range from 300,000 g/mol to 350,000 g/mol, in each case determined according to DIN EN ISO 13885-2 (2021-11) with N,N-dimethylacetamide as eluent and polystyrene as standard.
• Mw average molecular weight
• the at least one polymer (A) has a glass transition temperature in the range from -100 °C to 80 °C determined according to DSC (differential scanning calometry) DIN EN ISO 11357-1 (2017-02).
• the at least one polymer (A) is at least one partially crystalline Polyurethane polymer with a melting temperature in the range of 35 to 80 °C and a melting enthalpy of ⁇ 15 J/g, each determined by DSC at a heating rate of 20 K/min according to DIN EN ISO 11357-1:2017-02.
• the proportion of component (A) in the aqueous adhesive formulation is 5% by weight to 85% by weight, preferably 27% by weight to 80% by weight, of component (A).
• the aqueous adhesive formulation according to the invention and the kit-of-parts according to the invention contain as component (B) at least one semi-crystalline or crystalline polyurethane polymer containing carboxyl groups, which has a melting temperature in the range from 35 to 80 °C, an enthalpy of fusion of ⁇ 15 J/g, in each case determined by means of DSC (differential scanning calometry) at a heating rate of 20 K/min in accordance with DIN EN ISO 11357-1:2017 (2017-02), and a partial acid number in the range from 1.25 mg KOH/g to 25 mg KOH/g, determined in accordance with DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• component (B) at least one semi-crystalline or crystalline polyurethane polymer containing carboxyl groups, which has a melting temperature in the range from 35 to 80 °C, an enthalpy of fusion of ⁇ 15 J/g, in each case determined by means
• the polyurethane suitable as component (B) has a melting enthalpy of ⁇ 35 J/g, preferably ⁇ 40 J/g, particularly preferably ⁇ 45 J/g, in each case determined by means of DSC (differential scanning calometry) at a heating rate of 20 K/min in accordance with DIN EN ISO 11357-1:2017 (2017-02).
• the mixture of these polymers has an average partial acid number in the range of 1.25 mg KOH / g to 25 mg KOH / g, determined according to DIN EN ISO 2114: 2000 (2002-06, method A with an acetone-ethanol solvent mixture), wherein preferably each of the polymers in the mixture has a partial acid number in the range of 1.25 mg KOH / g to 25 mg KOH / g, determined according to DIN EN ISO 2114: 2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• the mixture of these polymers has an average melting temperature in the range from 35 to 80 °C and an enthalpy of fusion of ⁇ 15 J/g, each determined by means of DSC (differential scanning calometry) at a heating rate of 20 K/min in accordance with DIN EN ISO 11357-1:2017 (2017-02), wherein preferably each of the polymers in the mixture has a melting temperature in the range from 35 to 80 °C and an enthalpy of fusion of ⁇ 15 J/g, each determined by means of DSC (differential scanning calometry) at a heating rate of 20 K/min in accordance with DIN EN ISO 11357-1:2017 (2017-02).
• the polyurethane suitable as component (B) is structurally different from the polymer (A), in particular the polyurethane suitable as component (A).
• the polyurethane suitable as component (B) is preferably film-forming, preferably film-forming with a minimum film bonding temperature according to DIN 53 787 in the range from 0 to 100 °C, particularly preferably between 0 and 35 °C, and can be, for example, a single polyurethane containing carboxyl groups, or a mixture of at least two different polyurethanes containing carboxyl groups.
• the crosslinking reaction with carbodiimide groups occurs predominantly or exclusively via the incorporated carboxyl groups in the polyurethane suitable as component (B).
• Suitable as component (B) are all semi-crystalline or crystalline polyurethane polymers containing carboxyl groups known to the person skilled in the art which have a melting temperature in the range from 35 to 80 °C, an enthalpy of fusion of ⁇ 15 J/g, each determined by means of DSC (differential scanning calometry) at a heating rate of 20 K/min in accordance with DIN EN ISO 11357-1:2017 (2017-02), and a partial acid number in the range from 1.25 mg KOH/g to 25 mg KOH/g, determined in accordance with DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• a polyurethane polymer suitable as component (B) is/are generally one or more polyurethanes in the narrower sense, i.e. those polymers which are obtained by polymerizing polyols and polyisocyanates, but they can also be those in which mono- and/or diamines are used as structural components, optionally as chain extenders.
• the polyurethane polymer of component (B) is therefore generally at least one polyurethane, at least one polyurea and/or at least one polyurethaneurea.
• suitable components for building up the polyurethane polymer suitable as component (B) are, for example, the components a) to e) of the polyurethane polymer suitable as component (A) described above.
• the polyurethane polymer suitable as component (B) contains further components which are or are incorporated into the polyurethane polymer (B).
• compounds with carboxyl groups and crystalline or semi-crystalline difunctional polyester polyols are incorporated into the polyurethane polymer (B).
• Compounds containing carboxyl groups which are suitable as a structural component for the polyurethane polymer (B) used as component (B) according to the invention are, for example, diamino compounds or dihydroxy compounds which additionally carry carboxyl groups.
• Examples of such compounds are dimethylolpropionic acid, dimethylolbutyric acid and/or reaction products in the sense of a Michael addition of 1 mol of diamine such as 1,2-ethanediamine or isophoronediamine with 2 mol of acrylic acid or maleic acid.
• These can be used additionally as component a), as described in the description of component (A).
• Particularly preferred as a building block containing carboxyl groups, such as the described building blocks a) in component (B), is dimethylolpropionic acid.
• Other compounds containing carboxyl groups which are suitable as component e) for the polyurethane polymer (B) used according to the invention are, for example, aminocarboxylic acids which contain at least one isocyanate-reactive amino group and are thus incorporated into the polymer during the production of the polyurethane polymers suitable as component (B) by reaction with component e).
• aminocarboxylic acids which contain at least one isocyanate-reactive amino group and are thus incorporated into the polymer during the production of the polyurethane polymers suitable as component (B) by reaction with component e).
• Linear aliphatic, branched aliphatic, aliphatic-aromatic and aromatic aminocarboxylic acids are suitable.
• suitable compounds are aminocarboxylic acids with a primary or secondary amino group, such as alanine, lysine, glutamine, 6-aminohexanoic acid, aminoundecanoic acid, 8-aminooctanoic acid, 5-aminopentanoic acid, 4-aminobutyric acid, aminobenzoic acid, 4-aminomethylcyclohexanecarboxylic acid, 2-aminohexanoic acid, 4-aminocyclohexanecarboxylic acid, 12-aminododecanoic acid and 9-aminoononacarboxylic acid.
• aminocarboxylic acids with a primary or secondary amino group such as alanine, lysine, glutamine, 6-aminohexanoic acid, aminoundecanoic acid, 8-aminooctanoic acid, 5-aminopentanoic acid, 4-aminobutyric acid, aminobenzoic acid, 4-aminomethylcycl
• aminocarboxylic acids suitable building blocks e) in component (B) are used as carboxyl group-containing building blocks and particularly preferably aminoalkylcarboxylic acids such as 6-aminohexanoic acid and/or lysine, which are contained in the polymer in a form incorporated via the amino group.
• the building blocks containing carboxyl groups can also be used directly in their salt form, as carboxylate, or neutralizing agents leading to salt formation can be added during or after the production of the polyurethanes
• Tertiary amines that are particularly suitable and preferred for salt formation are, for example, triethylamine, dimethylcyclohexylamine, and ethyldiisopropylamine. Triethylamine is particularly preferred.
• amines can also be used to form salts, such as ammonia, diethanolamine, triethanolamine, dimethylethanolamine, methyldiethanolamine, aminomethylpropanol and mixtures of the above and other amines. It makes sense to add these amines only after the isocyanate groups have been largely converted.
• neutralizing agents such as sodium, potassium and/or lithium hydroxide
• the type and amount of neutralizing agents used, if any, must be selected so that carboxyl groups are still present in the polymer used as component (B) when these are reacted with polycarbodiimides.
• Crystalline or semi-crystalline difunctional polyester polyols suitable as structural component b) in component (B) are in particular linear or slightly branched polyester polyols based on dicarboxylic acids and/or their derivatives, such as anhydrides, esters or acid chlorides and preferably aliphatic, linear polyols. Mixtures of dicarboxylic acids and/or their derivatives are also suitable. Suitable dicarboxylic acids are, for example, adipic acid, succinic acid, sebacic acid or dodecanedioic acid. Succinic acid, adipic acid and sebacic acid and mixtures thereof are preferred, succinic acid and adipic acid and mixtures thereof are particularly preferred, and adipic acid is very particularly preferred. These are used in amounts of at least 90 mol%, preferably from 95 to 100 mol%, based on the total amount of all carboxylic acids.
• the difunctional polyester polyols b) can be prepared, for example, by polycondensation of dicarboxylic acids with polyols.
• the polyols preferably have a molecular weight of 62 to 399 g/mol, consist of 2 to 12 C atoms, are preferably unbranched, difunctional and preferably have primary OH groups.
• polyols which can be used for the preparation of the polyester polyols b) are polyhydric alcohols, such as ethanediol, di-, tri-, tetraethylene glycol, 1,2-propanediol, di-, tri-, tetrapropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-dihydroxycyclohexane, 1,4-dimethylolcyclohexane, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol or mixtures thereof.
• polyhydric alcohols such as ethanediol, di-, tri
• Preferred polyol components for the polyester polyols b) are 1,2-ethanediol, 1,4-butanediol and 1,6-hexanediol, particularly preferred are 1,4-butanediol and 1,6-hexanediol, and very particularly preferred is 1,4-butanediol.
• the polyester polyols b) can be composed of one or more polyols. In a preferred embodiment of the present invention, they are composed of only one polyol.
• the crystalline or semi-crystalline difunctional polyester polyols with a number-average molecular weight of at least 400 g/mol and a melting temperature of at least 35 °C have a melting enthalpy of at least 50 J/g
• the polymer produced using the same regularly has a melting enthalpy of ⁇ 15 J/g.
• the melting enthalpy of the polymer can be adjusted by slightly changing the content of polyester polyol b) in the composition or by slightly varying the melting enthalpy of the polyester polyol.
• polyester polyols b The preparation of polyester polyols b) is known from the prior art.
• the number-average molecular weight of the polyester polyols b) is preferably 400 to 4000 g/mol, more preferably 1000 to 3000 g/mol, particularly preferably 1500 to 2500 g/mol, very particularly preferably 1800 to 2400 g/mol.
• the melting temperature of the crystalline or semi-crystalline polyester polyols is generally at least 35 °C, preferably 40 to 80 °C, particularly preferably 42 to 60 °C.
• the enthalpy of fusion is ⁇ 15 J/g, preferably ⁇ 40 J/g and particularly preferably ⁇ 50 J/g
• the polyurethane polymers suitable as component (B) can be present and used as a solid solution or as a dispersion in a liquid medium.
• the polyurethane polymers are preferably provided as aqueous dispersions.
• Such polyurethane dispersions suitable as component (A) preferably have non-volatile fractions of 15% by weight to 70% by weight, preferably 20% by weight to 60% by weight, based on the total weight of the polyurethane dispersions.
• the pH is preferably in the range from 4 to 11, preferably 5 to 8.
• the average particle sizes determined by laser diffraction are usually in the range from 20 nm to 750 nm, preferably in the range from 30 nm to 450 nm.
• Polyurethane dispersions suitable as component (B) are preferably anionically stabilized polyurethane dispersions.
• An example of a commercially available polyurethane dispersion suitable as component (B) is Dispercoll ® U 2824 from Covestro GmbH AG.
• the at least one polymer suitable as component (A) and the at least one polyurethane polymer suitable as component (B) are preferably present in a mixing ratio such that the dried adhesive film has the following proportions: at least 30% by weight, preferably at least 40% by weight, particularly preferably at least 40% by weight to 89% by weight of the at least one polymer suitable as component (A), based on the total weight of components (A) and (B) as 100% by weight.
• the average molecular weight (Mw) of polymer (A) is ⁇ the average molecular weight (Mw) of polyurethane polymer (B), preferably the average molecular weight (Mw) of polymer (A) is greater than the average molecular weight (Mw) of polyurethane polymer (B), each determined according to DIN EN ISO 13885-2 (2021-11) with N,N-dimethylacetamide as eluent and polystyrene as standard.
• the at least one polyurethane polymer (B) has an average molecular weight (Mw) in the range from 20,000 g/mol to 300,000 g/mol, preferably in the range from 20,000 g/mol to 200,000 g/mol, particularly preferably in the range from 20,000 g/mol to 100,000 g/mol, even more preferably in the range from 40,000 g/mol to 80,000 g/mol, in each case determined according to DIN EN ISO 13885-2 (2021-11) with N,N-dimethylacetamide as eluent and polystyrene as standard.
• Mw average molecular weight
• the polyurethane polymer (B) has a partial acid number in the range from 2.5 mg KOH/g to 25 mg KOH/g, preferably in the range from 2.5 mg KOH/g to 12.5 mg KOH/g, each determined according to DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• the proportion of component (B) in the aqueous adhesive formulation is 10% by weight to 70% by weight, preferably 17% by weight to 70% by weight, of component (B).
• aqueous adhesive formulation according to the invention and the kit-of-parts according to the invention contain as component (C) at least one polycarbodiimide, and/or at least one polyaziridine and/or a mixture thereof.
• the aqueous adhesive formulation according to the invention and the kit-of-parts according to the invention contain at least one polycarbodiimide as component (C).
• polycarbodiimide is understood to mean compounds which contain more than one carbodiimide structural unit.
• Suitable polycarbodiimides preferably have the structure of formula I as part of the molecular structure: wherein n is an integer of 2 or more, preferably 2 to 50, most preferably 3 to 6; and R is preferably one or more of the following groups: an aliphatic organic group, an alicyclic organic group, and an aromatic organic group containing C and H atoms.
• Suitable polycarbodiimides can be prepared by generally known processes, for example by decarboxylation condensation of diisocyanates, such as aromatic diisocyanates, aliphatic diisocyanates and alicyclic diisocyanates.
• diisocyanates such as aromatic diisocyanates, aliphatic diisocyanates and alicyclic diisocyanates.
• diisocyanates such as aromatic diisocyanates, aliphatic diisocyanates and alicyclic diisocyanates.
• diisocyanates such as aromatic diisocyanates, aliphatic diisocyanates and alicyclic diisocyanates.
• diisocyanates such as aromatic diisocyanates, aliphatic diisocyanates and alicyclic diisocyanates.
• diisocyanates such as aromatic diisocyanates, aliphatic diisocyanates and alicyclic diisocyanates.
• diisocyanates such as aromatic diiso
• Particularly preferred polycarbodiimides are obtained by decarboxylation condensation of 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane and/or 4,4'-diisocyanatodicyclohexylmethane.
• the preparation is preferably carried out by heating at least one diisocyanate in the presence of a suitable catalyst, such as phospholine oxide, to 100 to 250°C with carbon dioxide elimination until the desired degree of conversion is reached.
• a suitable catalyst such as phospholine oxide
• the course of the reaction can be monitored, for example, by the decrease in the concentration of isocyanate groups in the reaction mixture.
• the reaction mixture thus obtained, which contains isocyanate groups is then reacted with at least one hydroxy-functional polyether based on ethylene oxide or based on ethylene and propylene oxide, with a reaction optionally taking place simultaneously or subsequently with further hydroxy- and/or amino-functional and/or other isocyanate-reactive compounds such as butyl glycol and optionally subsequently dispersing, emulsifying or dissolving.
• Suitable polycarbodiimides are, for example, Carbodilite ® SV-02, Carbodilite ® V-02-L2 and Carbodilite ® E-02 (all from Nisshinbo Industries, Tokyo, Japan) as well as Desmodur ® 2802 from Covestro GmbH AG.
• Preferred polycarbodiimides are Desmodur ® 2802 and Carbodilite ® V-02-L2, with Desmodur ® 2802 being particularly preferred.
• Suitable polyaziridines for use according to the invention are the compounds known to those skilled in the art which contain more than one aziridine group which is reactive with carboxyl groups.
• Examples of commercially available polyaziridines are PZ-28 and PZ-33 from Polyaziridine, LLC, Medford, NJ, USA, HD-105 from Shanghai Holdenchem CO, Ltd, Shanghai, China, and Neoadd Pax ® 521, 523 and Crosslinker CX-100 from Covestro, and Xama 7 from ichemco Co, Italy.
• Crosslinker CX-100 from Covestro reaction mass of 2-ethyl-2-[[3-(2-methylaziridin-1-yl)propionyl]methyl]propane-1,3-diyl bis(2-methylaziridin-1-propionate) and 2,2-bis( ⁇ [3-(2-methylaziridin-1-yl)propanoyl]oxy ⁇ methyl)butyl3-[2,2-bis( ⁇ [3-(2-methylaziridin-1-yl)propanoyl]oxy ⁇ methyl)butoxy]propanoate) is particularly preferred.
• the polycarbodiimide and/or the polyaziridine can be present and used in the form of a dispersion, a solution, a solid or a liquid, preferably it is used in the form of an aqueous dispersion.
• component (C) is at least one polycarbodiimide.
• component (C) has an average molecular weight (Mw) in the range from 500 g/mol to 50,000 g/mol, particularly preferably in the range from 1,000 g/mol to 20,000 g/mol, even more preferably in the range from 2,000 g/mol to 5,000 g/mol, determined according to DIN EN ISO 13885-2 (2021-11) with N,N-dimethylacetamide as eluent and polystyrene as standard.
• the at least one component C) is a polycarbodiimide and has a glass transition temperature in the range from -100 °C to 50 °C, preferably in the range from -60 °C to 35 °C, particularly preferably in the range from -60 °C to 30 °C, even more preferably in the range from -50 °C to 29 °C determined according to DSC (differential scanning calometry) DIN EN ISO 11357-1 (2017-02).
• DSC differential scanning calometry
• the proportion of component (C) in the aqueous adhesive formulation is 1% by weight to 30% by weight, preferably 3% by weight to 20% by weight, of component (C).
• aqueous adhesive formulation according to the invention and the kit-of-parts according to the invention can optionally contain as component (D) at least one further polymer which is different from the at least one polymer (A) and the at least one polyurethane polymer (B).
• Suitable components (D) include, for example, polyvinyl ester, polyvinyl ether, polyvinyl alcohol, polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyurethane, polyurethane-polyurea, polyurethane-polyacrylate, polyester, polyacrylate and/or copolymers thereof.
• the polymers suitable as component (D) can be present and used as solids, solutions or as dispersions in a liquid medium. Preferably as dispersions or emulsions or aqueous or organic solutions. Dispersions containing component (D) can also be mixed with other aqueous or solvent-containing oligomers or polymers and used together. With such mixtures, the compatibility must be tested in each case by means of simple preliminary tests.
• the proportion of component (D) in the aqueous adhesive formulation is 0% by weight to 30% by weight, preferably 0% by weight to 25% by weight, of component (D).
• the at least one polymer (D) has a partial acid number in the range from 0 mg KOH/g to 1 mg KOH/g, preferably in the range from 0 mg KOH/g to 0.05 mg KOH/g, in each case determined according to DIN EN ISO 2114:2000 (2002-06, method A with an acetone-ethanol solvent mixture).
• the at least one polymer (D) has no carboxyl groups and/or carboxylate groups. In a preferred embodiment, the at least one polymer (D) has no sulfone groups and/or sulfonate groups.
• the aqueous adhesive formulation according to the invention and the kit-of-parts according to the invention may optionally contain at least one additive which is different from components (A), (B), (C) and (D).
• An additive is understood to mean all binders, auxiliary materials and additives known in coating and adhesive technology, in particular emulsifiers and light stabilizers such as UV absorbers and sterically hindered amines (HALS), as well as antioxidants, fillers and auxiliary materials, e.g. anti-settling agents, defoamers and/or wetting agents, flow control agents, reactive thinners, plasticizers, neutralizers, catalysts, auxiliary solvents and/or thickeners and additives such as pigments, dyes or matting agents. Tackifiers can also be added as an additive.
• the additives are different from components (A), (B), (C) and (D).
• the additives can be added to the products according to the invention immediately before processing. They can be added alone or with components (A), (B), (C) and (D). Preferably, components (A), (B), (C) and (D) are added as dispersions in an aqueous medium. However, it is also possible to add at least some of the additives before or during dispersion of the binder.
• aqueous adhesive formulations according to the invention are preferably prepared by mixing the components with one another.
• the present invention therefore also relates to a process for producing the aqueous adhesive formulation according to the invention by mixing the individual components.
• the process according to the invention for producing the aqueous adhesive formulation according to the invention, as well as the production of the individual solutions or dispersions used, can generally be carried out under all conditions that appear suitable to the person skilled in the art, for example at a temperature of 18 to 28 °C, ideally at room temperature (23 °C), more preferably in equipment known to the person skilled in the art, for example in stainless steel, glass or enameled process equipment.
• rust formation and soluble metal alloys including from aluminum containers, must be avoided.
• the present invention further relates to the method according to the invention for producing an adhesive bond between substrates, wherein an adhesive formulation according to the invention is applied to at least one substrate, then dried and optionally heated to a temperature in the range from 40°C to 200°C, preferably 50°C to 120°C, particularly preferably 55°C to 100°C, and then bonding takes place.
• the substrate is preferably one or more of the following: wood, plastic, metals and alloys, chipboard, MDF boards, ceramics, stone, concrete, bitumen, hardboard, glass, glass fibers, carbon fibers, carbon nanotubes, porcelain, plastics, leather, textiles and/or textile fibers of various types, fabric, artificial leather, paper, cardboard, EVA, rubber, leather hide, ethylene-vinyl acetate copolymer, polyolefin, thermoplastic polyurethane, polyurethane foam, polymer fibers and graphite fibers.
• the substrates can be pretreated to improve the adhesion of the adhesive film to the substrate.
• Useful pretreatments include corona, plasma, flame, chemical priming, and combinations thereof.
• the aqueous adhesive formulation according to the invention is also suitable for bonding rubber materials such as natural and synthetic rubbers, various plastics such as polyurethanes, polyvinyl acetate, polyvinyl chloride, in particular plasticized polyvinyl chloride.
• the adhesives are also suitable for bonding thermoplastics such as ABS (acrylic butadiene styrene), PC (polycarbonate) and mixtures thereof, as well as polyolefinic plastics, if necessary after suitable pretreatment.
• aqueous adhesive formulation according to the invention is carried out according to the known methods of coating technology or adhesive technology with regard to the applications and processing of aqueous dispersions or aqueous emulsions or aqueous solutions.
• Applying may mean applying the adhesive to the entire surface of the substrate or only to one or more parts of the substrate surface.
• the "application” can be done by brushing, dipping, spraying, rolling, doctoring, flowing, pouring, printing or transfer printing, preferably by brushing, dipping or spraying.
• heating and drying of the substrate surface to which the adhesive is applied may refer only to heating and drying the substrate surface or to heating and drying part or all of the substrate including the substrate surface to which the adhesive is applied.
• the "heating and drying” process can remove a volatile component.
• the volatile component can be water.
• heating and drying is preferably carried out by one or more of the following means: infrared heat radiation, near infrared heat radiation, microwaves and use of a convection oven at elevated temperature.
• the heating temperature is as high as possible, but should not exceed the temperature limit at which the substrate is deformed uncontrollably or otherwise damaged.
• the thermal activation process is often used.
• the adhesive layer is activated by heating, e.g. with an infrared radiator, and converted into an adhesive state.
• the temperature at which the adhesive film becomes tacky is referred to as the activation temperature.
• the "bringing into contact” preferably takes place before the temperature of the substrate surface is lower than the temperature at which the adhesive is bondable, and preferably before the temperature of the substrate surface is not below 55 °C.
• the substrate surface treated in step iv is preferably contacted with the substrate itself or an additional substrate within one hour, more preferably within 30 minutes, even more preferably within 10 minutes, and most preferably within 5 minutes to obtain the bound product.
• the additional substrate can be any substrate that needs to be bonded.
• the additional substrate may be identical to the substrate or different from it.
• the additional substrate is preferably coated, heated and activated with heat.
• a further cooling treatment may be carried out to reduce the temperature of the bonded product to room temperature.
• the method of heat application is preferably one or more of the following: use of a convection oven or infrared heat radiation, near infrared heat radiation, microwaves, and heat transfer through an article that comes into contact with the substrate coated with the adhesive of the invention.
• a further object of the present invention is the use of the aqueous adhesive formulation according to the invention for producing latent-reactive adhesive layers, self-supporting, latent-reactive adhesive films and latent-reactive adhesive powders.
• a further object of the present invention is the use of latent-reactive adhesive layers, self-supporting, latent-reactive adhesive films and latent-reactive adhesive powders, each containing the aqueous adhesive formulation according to the invention, for bonding or joining substrates.
• the aqueous adhesive formulation in the form of an aqueous dispersion can also be applied to release paper (e.g. silicone paper or polyolefinic non-stick paper or similar carrier materials) using a spray, doctor blade, brush or roller application method. After drying, self-supporting latent-reactive films or fleeces are obtained, which can be wound up after inserting a release paper if necessary and stored as an adhesive film until they are used.
• release paper e.g. silicone paper or polyolefinic non-stick paper or similar carrier materials
• a latent-reactive adhesive powder in the form of a granulate or powder can be obtained from the aqueous adhesive formulation in the form of an aqueous dispersion by suitable technical processes.
• the water can be removed from the aqueous adhesive formulation in the form of an aqueous dispersion by spray drying.
• Another way to produce latent-reactive powders is to freeze out at least some of the components contained in the aqueous adhesive formulation in the form of an aqueous dispersion at temperatures below 0°C. The resulting solids are then largely freed from the water by filtration, centrifugation, etc. and finally dried. The coarse-grained powder obtained can then be brought to the required particle size by suitable grinding, e.g. in ball mills, bead mills, sand mills or jet mills.
• a further object of the present invention is the use of the kit-of-parts according to the invention for producing latent-reactive adhesive layers, self-supporting, latent-reactive adhesive films and latent-reactive adhesive powders.
• a further subject matter of the present invention is the use of the aqueous adhesive formulation according to the invention for bonding wood, paper, thermoplastics, elastomeric plastics, thermoplastic-elastomeric plastics, vulcanizates, textile fabrics, knitted fabrics, braids, leather, metals, ceramics, asbestos cement, stoneware, concrete, foams, in each case to one another and/or to porous substrates, preferably with a density of less than 1 kg/liter, in particular for bonding foams in mattress, furniture and/or upholstery production.
• a further subject matter of the present invention is an article produced using the aqueous adhesive formulation according to the invention, wherein the article is preferably a molded part laminated with thermoplastic film, preferably made of plastic, wood or a wood-based material such as MDF.
• the article is a shoe or a piece of furniture.
• the aqueous adhesive formulation according to the invention developed here can also be used in other applications, such as for example in the bonding of automotive interior parts.
• Polyester I Polyesterdiol from 1,4-butanediol and adipic acid, OH number 50
• Polyester II Polyesterdiol from 1,6-hexanediol, neopentyl glycol and adipic acid, OH number 56
• Polyester III Polyesterdiol from 1,6-hexanediol and adipic acid, OH number 50
• Desmodur ® H Hexamethylene diisocyanate-1,6 (Covestro GmbH AG, Leverkusen/DE)
• Desmodur ® I Isophorone diisocyanate (Covestro Deutschland AG, Leverkusen/DE)
• Botamul ® 1820 liq Emulsifier, 15 wt.% solution of stearyl alcohol polyglycol ether in water (LEVACO Chemicals GmbH, Leverkusen)
• Desmodur ® 2802 is a hydrophilically modified polycarbodiimide with a non-volatile content of 40 wt. %, a carbodiimide group content of about 1.4 meq DCC/g), a weight-average molecular weight Mw of 3258 and an average carbodiimide group functionality of 4.5, obtained from Covestro AG.
• a carbodiimide concentration of 3.5 meq DCC is calculated for the dried polycarbodiimide from the non-volatile content and the carbodiimide group content.
• the glass transition temperature is -30°C.
• Dispercoll ® U 2824 (Covestro GmbH AG, Leverkusen/D) is a carboxylate-stabilized polyester polyurethane dispersion containing dimethylpropionic acid as a structural component (non-volatile portion of the dispersion 40%).
• the polymer contained is partially crystalline in the DSC measurement.
• the polyurethane dispersion has a partial acid number of 4.0 mg KOH/g.
• the partial acid number of the dried polymer is 10 mg KOH/g.
• the dried dispersion polymer has a melting enthalpy of 51 J/g and a melting temperature of approx. 47 °C.
• the average molecular weight Mw is 65,000 g/mol.
• Dispercoll ® U XP 2643 (Covestro GmbH AG, Leverkusen/D) is a carboxylate-stabilized polyurethane dispersion based on a polyether and dimethylpropionic acid (non-volatile portion of the dispersion 40%).
• the dried polymer shows no melting peak in the DSC measurement, the glass transition temperature is - 51 °C.
• the product has an acid number of 4.0 mg KOH/g.
• the partial acid number of the dried polymer is 10 mg KOH/g.
• the average molecular weight Mw is 64,000 g/mol.
• Dispercoll ® U 42 (Covestro Deutschland AG, Leverkusen/D) is a sulfonate-stabilized polyurethane dispersion based on a polyester (solids content of the dispersion 50%).
• the dried polymer shows no melting peak in the DSC measurement, the glass transition temperature is -5 °C.
• the partial acid number is 0 mg KOH/g.
• the average molecular weight Mw is 219,000 g/mol.
• polyester III 578 g were dewatered for 1 hour at 110°C and 15 mbar. At 60°C, 9.9 g of 1,4-butanediol were added with stirring. Then, at 80°C, 40.7 g of Desmodur ® I and 62.1 g of Desmodur ® H were added and the mixture was stirred at 100°C until a constant isocyanate content of 2.2% was reached. The reaction mixture was dissolved in 1038 g of acetone. and cooled to 48°C.
• a solution of 21.8 g of sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid, 4.7 g of ethylenediamine in 36.6 g of water was added to the homogeneous solution with vigorous stirring. After 30 minutes, dispersal was carried out by adding 976 g of water. After distillative separation of the acetone, an aqueous polyurethane-polyurea dispersion with a non-volatile content of 40% was obtained.
• the dried dispersion polymer has a melting enthalpy of approx. 56 J/g and a melting temperature of approx. 51 °C, as well as a glass transition temperature of -54 °C.
• the average molecular weight Mw is 330,000 g/mol.
• the partial acid number of the dried polymer is 0.9 mg KOH/g.
• polyester I and 42.67 g of polyester II were dewatered for 1 hour at 110 °C and 15 mbar A.
• 2.24 g of 1,4-butanediol and then a mixture of 38.02 g of Desmodur ® H and 25.11 g of Desmodur ® I were added with stirring.
• the mixture was heated to 80 °C and stirred until a constant isocyanate content of 1.30 wt.% was reached.
• the reaction mixture was dissolved in 770 g of acetone and cooled to 48 °C.
• aqueous adhesive dispersions listed in Table 1 are weighed one after the other into a plastic cup with a screw-on lid. Mixing is carried out at 1000 revolutions per minute for 3 minutes in the Speedmixer ® .
• the determination of the partial acid number is carried out according to DIN EN ISO 2114:2000 (2002-06, method A), whereby a solvent mixture of 2 parts by volume of acetone (5.4) and 1 part by volume of ethanol (5.5) was used instead of the solvent mixture of 2 parts by volume of toluene (5.7) and 1 part by volume of ethanol (5.5) described under 5.1.
• the partial acid number of the dried polymer corresponds to the partial acid number of the solid resin described in 8.1.2 and is calculated analogously.
• the non-volatile components of the polymer dispersions were determined according to DIN EN ISO 3251, initial weight 1 g, drying for 1 h at 125 °C.
• the glass transition temperatures, melting temperatures and enthalpies of fusion were determined by differential scanning calorimetry (DSC) using a DSC Q2000 calorimeter from TA Instruments.
• a film was prepared by doctoring the dispersion with a wet film thickness of 100 ⁇ m on a glass plate, pre-dried for 2 hours at 23°C and 50% relative humidity, the coated The glass plate is then transferred to a dry box and stored there for 3 days at 23°C and 0% relative humidity.
• the coated glass plate is removed from the drying box and approx. 5 mg of sample material is used for the DSC measurement.
• Tg glass transition temperatures
• the glass temperature corresponds to the temperature at half the height of the glass transition, whereby the third heating was evaluated. If no glass transition temperature can be determined, the measurement program is changed as follows: Rapid cooling to the starting temperature of -140 °C, then the start of three heating cycles from -140 °C to +150 °C with a heating rate of 20 K/min and a cooling rate of 320 K/min.
• the first heating is used to determine the melting temperatures; the melting temperatures given correspond to the peak crystallization temperatures.
• the first heating is used to determine the enthalpies of fusion.
• the enthalpies of fusion of all melting peaks with a peak melting temperature Tp,m in the range of 15 to 80 C are added together. Peaks with enthalpies of fusion of >0.9 J/g are not considered.
• the molecular weight Mn, Mw, Mz is determined according to DIN EN ISO 13885-2:2021-11 using N,N-dimethylacetamide as eluent against a polystyrene standard.
• nCOOH partial acid number mg KOH / G ⁇ mass G / 56.1 mmol / mg KOH
• component (B) consists of several polymers, the amount of substance can be calculated for each polymer and the individual amounts of substance can be added together.
• the carbodiimide concentration is determined using ATR infrared spectroscopy on the Perkin Elmer Spectrum two device. (ATR is an abbreviation for "attenuated total reflection").
• dicyclohexylcarbodiimide DCC
• ethanol concentration: 0.1 mmol/g, 0.2 mmol/g, 0.5 mmol/g, 1.0 mmol/g, 1.5 mmol/g and 2 mmol/g.
• PA peak areas
• the aqueous dispersion is examined directly using ATR infrared spectroscopy.
• the carbodiimide concentration is determined using PA of the band at approx. 2118 cm-1.
• the carbodiimide concentration c of the aqueous dispersion [meq DCC/g] is calculated using the formula PA/m. From this, the carbodiimide concentration c) of the polycarbodiimide can be calculated, taking into account the non-volatile portion of the dispersion.
• the amount of carbodiimide groups nCDI [meq DCC] is determined from the carbodiimide concentration of component C) and the mass of component C) Mc.
• mCDI meq DCC Mc G ⁇ c meg DCC /G
• the carbodiimide concentration is as in the WO2020216680A1 described on a 25% solution in toluene and converted to the solid.
• the ratio of carbodiimide groups in component (C) to carboxylic acid groups in component (B) for Example 7 is 9.94 to 3.57 and 2.8:1, respectively.
• the softening point values were determined using a canvas-canvas composite combination.
• the adhesive dispersions are applied to the test specimens (25 mm x 50 mm) made of cotton fabric using a brush, resulting in adhesive surfaces measuring 20 mm x 10 mm.
• the adhesive layer is dried for 30 minutes at 23°C / 50% relative humidity.
• a second adhesive layer is then applied with a brush.
• the test specimens coated with adhesive are heat-activated for 10 seconds using the IR emitter from Funck (shock activation device 2000).
• the temperature of the surface of the adhesive layer rises to approx. 90°C.
• the adhesive bond is created immediately after heat activation by pressing the activated adhesive layers against each other for 1 minute in a press at 4 bar.
• the test specimens produced in this way are stored for 1 week in a standard climate (23°C / 50% relative humidity).
• the softening point values were determined using a canvas-canvas composite combination.
• the adhesive dispersions are applied to the test specimens (25 mm x 50 mm) made of cotton fabric using a brush, resulting in adhesive surfaces measuring 20 mm x 10 mm.
• the adhesive layer is dried for 30 minutes at 23°C / 50% relative humidity.
• a second adhesive layer is then applied using a brush.
• the adhesive layer is dried for 30 minutes at 23°C / 50% relative humidity.
• a second layer of adhesive is applied with a brush. Then it is dried for a further 60 minutes at 23°C / 50% relative humidity.
• the coated canvas substrates are stored for different periods of time (hours to weeks) in a standard climate (23°C / 50% relative humidity) before heat activation and joining.
• the open time is the maximum storage time after which a softening point of 100 °C or higher is still reached using the measurement method described below.
• test specimens coated with adhesive are heat-activated for 10 seconds using the IR emitter from Funck (shock activation device 2000).
• the temperature of the surface of the adhesive layer rises to approx. 90°C.
• the adhesive bond is created immediately after heat activation by pressing the activated adhesive layers against each other for 1 minute in a press at 4 bar.
• the test specimens produced in this way are stored for 1 week in standard conditions (23°C / 50% relative humidity).
• Comparative examples 1,3" 5,8,10,12 show that polyurethanes containing as well as those not containing carboxyl groups and mixtures thereof without the use of a polycarbodiimide do not lead to sufficient heat resistance of the adhesive bonds.
• Comparative Example 4 shows that a combination of an amorphous polymer dispersion containing carboxyl groups with a polycarbodiimide leads to adhesive bonds with sufficient heat resistance when immediately activated by heat, but the adhesive films do not show sufficient open time when stored under Standard conditions. After just 3 hours, the crosslinking of the adhesive films has progressed to such an extent that an adhesive bond with sufficient heat resistance can no longer be achieved during the joining process. The already crosslinked polymers obviously no longer have sufficient stickiness to form a heat-resistant adhesive bond at the selected activation temperature of 90 °C.
• Comparative Example 9 By combining a semi-crystalline polymer dispersion not containing carboxyl groups with an amorphous polymer dispersion containing carboxyl groups and a polycarbodiimide, a sufficient open time of the adhesive film is also not achieved.
• Example 11 according to the invention shows that a sufficient open time is achieved when the polymer not containing carboxyl groups is amorphous, but the polymer containing carboxyl groups is partially crystalline.
• Comparative example 2 which is based exclusively on a polymer dispersion containing carboxyl groups and a polycarbodiimide, shows an open time of more than 3 weeks, but the required use of polycarbodiimide is significantly higher and the open time is shorter than in examples 6 and 7 according to the invention.
• Examples 6, 7, 14, 15 and 16 according to the invention demonstrate that the use of polymer dispersions with a high molecular weight that do not contain carbonyl groups in combination with polymer dispersions that contain carboxyl groups, even with a small amount of polycarbodiimide, leads to high heat resistances when bonding both immediately after the adhesive has dried and after the dried adhesive layer has been stored for 1 week.
• the heat resistances in example 13 according to the invention (polymer dispersion with a lower molecular weight that does not contain carboxyl groups) with a comparably high polycarbodiimide content are somewhat lower immediately and after 1 week of storage.

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